…no? The first point, of course, but the author explicitly stated that. A fundamental (and non-controversial) aspect of “giftedness” is that the child learns at a much more rapid pace than peers. This almost automatically requires adjustments to curriculum that would not apply to a non-gifted child.
People do not learn at a constant speed throughout their education. Almost everyone has at least a few runs of "giftedness", at least in some subjects, where they could benefit from acceleration; and conversely, even gifted students might need some "remedial" effort from time to time.
A person with an IQ of 140 will learn pretty much every academic subject faster than someone with an IQ of 100. It’s kind of baked into the metric. Now, of course this doesn’t mean that they will have any advantage in learning, say, how to ride a bike or dribble a basketball, but the discussion here is clearly directed at “book learning” which comprises the majority of school curriculum.
I think the obsession with gifted learners being "different" from the "normal" is... weird. I look at the phenomenon as more of a "Here's how we cater to what we perceive as our best and brightest" ... when the reality is that everyone has the capacity to be bright, environment and competition just play a huge role.
I mean, my lifetime experience is one of "being different". I was fundamentally different from my classmates since day 1. Teachers picked up on it immediately and were concerned that, while I breezed through everything and seemed to be very "sharp" (or whatever funny word they would use), I was totally disinterested and seemed bored and unhappy. I was. I learned nearly everything I was shown instantly, and usually understood it effortlessly. In grade 3 I excelled so strongly at spelling that the teacher had me make the weekly spelling tests. In grade 5 I was the only kid who actually copied down and memorized "pneumonoultramicroscopicsilicovolcanoconiosis" and "phthatlylsulfithiazole" when the teacher wrote them on the board to be funny (though he spelled them wrong at the time, I later learned). FWIW I just typed those from memory without checking their spelling.
Environment surely does play some part. I grew up in a home that fostered intellect, learning, growth etc. I'm sure there are countless studies on "nature vs. nurture" and my subjective view is both are relevant, perhaps even fairly 50/50. But my life growing up I was the exception to the norm in all environments. I have some really stark examples that could really hit this home but I'm not going to post them on here, but... there's a lot of truth to the "differentness of giftedness".
Everyone is different, that is true. But taking that multifaceted existence and flattening it when really this discussion is only about one aspect of that existence (that effectively has already been flattened, but in some other way) is not nice. It tells folks who are quite simply better at some aspects of their life than other people that in fact they are not better, those other people are sometimes better too. But this is about learning. They are objectively better.
That means some folks are objectively worse - which doesn't mean they can't excel in some other area of life. That's not what's under discussion.